Neostigmine (Prostigmin)


  • Cholinergic Muscle Stimulant


  • Antimyasthenic


  • Myasthenia gravis

  • Neuromuscular blockade

  • Urinary Retention


  • No labeled contraindications


  • Pregnancy category C

Adverse Reactions (Side Effects):

  • Frequent: diarrhea, sweating, watery mouth, nausea, vomiting, stomach pain/cramps

  • Less frequent: increased bronchial secretions, urinary frequency, watery eyes



Administered orally (tablets, syrup), subcutaneously, intramuscularly, intravenously

  • Adult: 

    • Myasthenia gravis: 

      • PO 15mg every 3-4 hours, the dose and frequency adjusted as needed.  Maintenance; 150mg daily, the intervals of the doses determined by the patient response. 

      • IM/SQ 500mcg, subsequent doses based on patient response. Subsequent doses may be less than 500mcg. IV 500mcg to 2mg administered slowly, repeated as required up to 5mg  

      • Note: When neostigmine is administered IV, recommend 0.6-1.2mg atropine be administered IV prior to or concurrently to counteract muscarinic side effects. 

    • Postoperative urinary retention: 

      • IM/SQ 500mcg every 3 hours as needed; maximum of 5 doses before catherization

    • Antidote: (to nondepolarizing neuromuscular blockade) 

      • IV 500mcg to 2mg, repeated as required up to 5mg. Use atropine concomitantly as stated above.

  • Child: 

    • Myasthenia gravis: 

      • PO 2 mg/kg divided into 6-8 doses daily

      • IM/SQ 10-40mcg per kg body weight every 2 to 3 hours.  

      • Note: co-administer or administer on alternate doses 10mcg atropine to counteract muscarinic side effects.

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